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By Thomas E. Ban

The continuous sintering process was invented more than 60 years ago by two metallurgists, Arthur S. Dwight and Richard L. Lloyd, who saw a need for automation in mineral processing. Their specific objective was to beneficiate copper ore by desulfurizing and agglomerating it for copper blast furnace smelting at the Cananea plant in Mexico1. Since their early development the process expanded widely in scope, size, and application. The current worldwide sintering applications exceed 250 million tons per year for agglomerating ores of lead, manganese, zinc, and iron. Sintering is also widely used for production of sintered lightweight aggregate from clays, shales, and fly ash. The continuous sintering process took on wide expansion during the 1960's in foreign countries. Plants for production of approximately 135 million tons per year were built in these countries for sintering iron ore fines as shipped from new iron ore projects of Canada, Liberia, India, Brazil, and Australia. This expansion represented construction of approximately 80 new sintering plants, some as large as 15 thousand tons per day production on a single large sintering machine. Sized self-fluxing or highly fluxed sinter has become recognized as a premium blast furnace charge and has enabled blast furnaces of Japan and Europe to produce upwards of 10,000 tons of metal per day with coke rates less than 1,000 pounds per ton of metal. This coke requirement is practically 50 percent of the ordinary rates achieved during the early 1950's when the peak blast furnace production was less than 113 of the current records.

Jan 1, 1975

By M. H. Harrington

The Transaclions of the Institute afford abundant evidence of the general recognition by mining engineers of the importance of a safety-lamp which will not only give warning of the presence of fire-damp, but will also indicate the proportion in which it is present.' Mining-men are only too familiar with the frequent and sudden changes that habitually occur at the working-face of a gaseous mine. Nothing illustrates more forcibly the pregnant condition of the strata enfolding the seam and the seam itself, than the fact that a circulation of perhaps 150,000 cu. ft. of air

Jan 1, 1907

By L. L. Wyman

IN order to clarify and amplify the existing data concerning the action of the cementing material in cemented tungsten carbide alloys, the authors have initiated this investigation of the entire range of cobalt-tungsten carbide alloys. Inasmuch as the ultimate objective is relative to what actually goes on during the sintering of cemented tungsten carbide materials, this work was necessarily restricted to heat treatments similar to those used in actual production of these materials. In the course of numerous experiments, the authors have noted several conditions that indicated that there was a solubility to be considered. Among these factors are the following: 1. Many of the alloys showed a much larger amount of binding constituent to be present than could possibly be accounted for by the cobalt content. 2. In many areas, grains of the carbide constituent are much larger than the particles of carbide originally added. In addition, these grains are of very regular contour. 2a. In samples of cemented tungsten carbide which had been fused in the atomic hydrogen torch in the presence of excess hinder constituent, immense grains are formed, and their shapes are very regular. This is also true when the cemented tungsten carbide of 13 per cent. Co content is fused alone in the atomic hydrogen torch. Contrary to general expectation, chemical analysis of this material, after fusion in the atomic hydrogen torch, checks the analysis of unfused material. 3. In making the cemented tungsten carbide materials by the process of exerting the pressure at the time of heating a certain portion of the contents squeezed out of the mold. Chemical analysis has shown that this material contains approximately 12 to 20 per cent. of tungsten. The microstructure shows a cored dendritic structure interlaced with eutectic network, and some graphite, as shown in Fig. 1. 4. Thermal analysis of these materials has consistently indicated an arrest point close to 1350° C.

Jan 1, 1930

By G. S. Maré

Tin plating operations are of a complex nature due to the many operational variables that need to be controlled in order to create a product of required quality. The work in this report lays the basics for the control of a halogen plating operation based on the DuPont tinplating set-up with regard to the chemical make-up of the plating solution, as well as operational variables such as temperature and current density. To evaluate these aspects of the process, a rotating cathode Hull-cell set-up was used. This allowed for a laboratory scale plating arrangement that simulates industry closely with regard to chemical and hydro-dynamic considerations. Typical industry accepted standards were obtained for the values of operational variables and a ?baseline? test was conducted employing these standards. All subsequent tests conducted were benchmarked against this baseline result. A large suite of results was obtained in which it was found that changes could be made to the industry accepted norm which would improve on the stability of the operation and therefore the quality of the final tin-plated product. Examples of these results are: an increase in stannous tin concentration, an increase in sodium chloride concentration and a slightly elevated plating temperature. In addition, conditions were found that must be avoided to prevent instability and poor product quality.

Jan 1, 2010

By D. Harrington

Although the explosion-fatality record for the fiscal year 1944 showed considerable improvement over those of the preceding 4 years, it is still fur from creditable, and the coal-mining industry and agencies interested in the prevention of coal-mine accidents should not be satisfied until accidents from explosions and fires are eliminated. In view of present knowledge of the methods of preventing explosions and fires, such disasters are inexcusable and discredit the mining industry. Despite this knowledge, far too many coal¬mine operators and employees continue to follow procedures that have resulted in disasters in the past. Included in the appendix to this circular are a number of safety measures designed to prevent coal-mine explosions and fires and metal-mine fires. Their adoption is essential if explosions and fires are to be prevented, as certainly they should be. An epidemic of disastrous mine fires of electrical origin during the past 2 years emphasizes the need for better methods of protection of underground electrical circuits. At present, committees of mining-electrical engineers, electrical-equipment manufacturers' representatives, and others are cooperating with the Bureau of Mines seeking means to solve this problem.

Jan 1, 1945

By P. K. Fedotov

Centrifugal separation opens its new application fields in the Mining Industry. The up-to-date equipment for ultra-fine ore and concentrates grinding allows an efficient use of centrifugal concentration for micronic gold grains recovery. Moreover, advanced centrifugal concentrators are presented on the market: concentrators with continuous concentrate discharge designed both for ore and non-metallic minerals concentration process. The conducted tests proved the centrifugal concentration to be efficient process for gold recovery from finely ground concentrates and ores (less than 20 µm). Knelson concentrator application for such a fine material in different process circuits makes possible to raise the total gold recovery level of plants. In the circuits of coal plants and in course of coal slimes treatment the centrifugal concentration may be used before flotation in order to improve process performances. A centrifugal concentrator KC-CVD with continuous concentrate discharge working on 0.3 (0.5)mm fraction before flotation is

Jan 1, 2014

By Richard A. Walker, John P. Hager

The thermodynamic properties of the Pb-Au system have been determined between 750" and 1075°C by means of the cell Mo, Pb(1) |(PbO-SiO2){l) , SiO2(s) |Pb-Au(1), Mo The activities of lead and gold exhibit negative deviations from ideal behavior; the values of ? pb and ? the raoultain activity coefficients at infinite dilution, being 0.24 and 0.25, respectively, at 1200°K. The liquidus curve for the gold-rich region of the Pb-Au phase diagram has been determined from measure-ments on seven alloy compositions in the two phase region (liquid + Au(s)). The standard free energies of formation of Au2O(l) and Ag2O (1) have been estimated from cell measurements obtained by replacing the alloy electrode with pure liquid gold and silver. A new integral molar heat of mixing curve for the liquid Pb-Au system is presented and the results of previous studies discussed. The contribution of HM to FE was found to be small relative to TSE. THE use of galvanic cells of the type A(l) |A+Za|A - B(l) [I] provides an accurate means for the thermodynamic study of liquid alloy systems. In Part 1&apos; it was shown that cells of type [I] may be extended to higher temperatures and to a wider range of alloy systems if the ion A+Za is incorporated in an appropriate molten oxide phase, rather than in the classical fused salt electrolyte. In the following investigation the experimental method is extended to an investigation of the thermo-dynamic properties of the Pb-Au system by use of the cell: Mo, Pb(l) | (PbO-SiO2)(l), SiO2(S) |Pb-Au(l), Mo [] Previous measurements on liquid Pb-Au alloys were obtained by Kleppa2 by electromotive force measurements on a galvanic cell involving a molten chloride electrolyte. These measurements were confined to temperatures less than 830°C and compositions with X Pb > 0.2 because of the instability of the cell at higher temperatures. Later measurements by Kleppa3 on the heats of formation in the composition range 0.67 < Xpb < 0.98 were not consistent with the results by electromotive force measurement. The purpose of the present study is to extend the temperature and composition range of the thermodynamic properties and to obtain an independent measure of the integral molar heat of mixing over the entire composition range.

Jan 1, 1970

By T. M. Gurr

The United States is the world&apos;s leading producer of phosphate rock. In 1975 according to the U. S. Bureau of Mines&apos; statistics, 44.3 million tonnes (48.8 million short tons) of phosphate rock were produced in the United States&apos;, which is 40.6 percent of the world&apos;s production2. The major phosphate producing areas of the United States are located in Figure 1 and the production for 1975 is listed as follows: Million Million Short Tonnes Tons Florida and North Carolina 36.9 40.7 Western States 5.3 5.8 Tennessee 2.1 2.3 All of these areas produce phosphate from deposits which are sedimentary marine in origin. Occurrences of phosphate exist throughout the United States in numerous locations that are of both igneous and sedimentary origins. However, these other phosphate occurrences vary greatly in extent and economic significance. Georgia, South Carolina, California, Texas, Arkansas, Kansas, Iowa, Alabama, Kentucky and Virginia are but a few of the states in which phosphate is thought or known to

Jan 1, 1977

By B. B. Cox

Iraq, formerly called Mesopotamia in Asiatic Turkey, became a kingdom under British Mandate after the world war and is expected to gain its independence in 1932 when it enters the League of Nations. The kingdom is shown on Fig. 1 in its relations to neighboring countries, to the Mediterranean Sea and to the Persian Gulf. It is slightly smaller than the State of Texas with its capitol, Baghdad, inland about as far from the Persian Gulf as Breckinridge, Tex., is from the Houston Shipping Channel. The oil fields lie 180 to 225 miles north of Baghdad, or about as far as from Breckinridge to Oklahoma City, and about as far from the Mediterranean as Fort Worth is from Hobbs, N. M. A narrow-gage railway runs from Basra, the Persian Gulf port, to Baghdad. From there another narrow-gage runs into the Kurdish hills east of the Tigris to Kirkuk. A standard-gage, part of the old Berlin-Baghdad system, follows the west bank of the Tigris northward from Baghdad to Baiji, a village about 100 miles south of Mosul. No railway exists between Iraq and the Mediterranean, though the Anatolian Railways in southern Turkey come to within 50 miles of the Iraq frontier and 120 miles of Mosul. Surveys have been completed for a railway through British Mandates from Haifa to Baghdad as well as for a railway through French Mandated Syria from Tripoli to Abu Kemal near the Iraq border. Wagon roads, excepting those constructed by the oil companies, are few and indifferent in Iraq and no road exists across the desert to the Mediterranean, but contrary to prevalent beliefs the surface is firm and free from sand dunes so that motor cars can go almost anywhere in dry weather, with ease. Frequent motor car and airplane service exists between Baghdad and the Mediterranean ports and motor car service may be had between Kirkuk and Nisibin, Turkey, where on two days each week through Wagons Lits service is available to Paris. Baghdad is about 21 days distant from New York City with present transport facilities. The climate is semiarid, similar to Imperial Valley, California, the average rainfall outside the mountainous parts amounting generally to

Jan 1, 1932

The following record of the important responsibilities already shouldered by Dr. Ricketts will give some indication of the trust and confidence reposed in him by his colleagues. The Institute is to be congratulated that a man who is already so much engaged should be willing to assume the further responsibility of guiding the Institute&apos;s Ship of state during the ensuing year. Louis Davidson Ricketts, who is brother of Professor Palmer or Chamberlaine Ricketts, President of Rensselaer Polytechnic Institute, was born at Elkton, Md., Dec. 19. 1859, was graduated from Princeton University in 1881 with the degree, Bachelor of Science, chosen a Fellow in Chemistry and W. S. Ward Fellow in Economic Geology, and after two years&apos; study given the degree Doctor of Science. Following the completion of Iris work at Princeton, Dr. Ricketts went to Colorado and started to work as a mine surveyor. For the 15 years following, his time was chiefly occupied in reconnaissance work, geological work and mine examination. From 1887 to 1890 Dr. Ricketts was Geologist for Wyoming, and at, the end of that period transferred his operations to the Southwest. where he has since been steadily engaged in large mining projects. He was identified with the acquisition of the property now owned by the Moctezuma Copper Co., a , subsidiary of Phelps, Dodge & Co., at Nacozari, Sonora, Mex. From 1899 to 1901 he was General Manager of the property and during his administration the concentrator and reduction works were completed and the mines put on a dividend-paying basis

Jan 3, 1916

By Daniel K. Dysinger

Capital resource budgeting is the way managers of publicly held companies fulfill their fiduciary responsibility to maximize the wealth of stockholders. Managers maximize shareholder wealth by allocating investment capital to the most productive of competing alternative projects. Managers do this in a manner that maximizes the net present value of the firm&apos;s future cash flow. The techniques of cash flow analysis are the primary tools available for selecting a corporate portfolio of projects that meets or exceeds the rate of return expected by shareholders. The reliability of cash flow analysis hinges on the ability of managers to forecast the future values of individual components of cash flow. The accuracy and reliabil¬ity of forecasting determine the soundness of capital investment decisions and, ultimately, determine the value of the firm.

Jan 1, 1997

By Lee R. Kump, Sarma V. Pisupati, Peter L. Rozelle, Alan R. Larson, Timothy S. White, Nicholas A. Crescenzo, Maureen D. Feineman

The Mercer Clay bed in central Pennsylvania has produced feedstocks for the refractory industry in the USA and has also been investigated as a source of alumina and lithium. Developments in global markets for these commodities, as well as rare earth elements, have led to their classification as critical minerals in the USA, in turn renewing production opportunities for the Mercer Clay resource. The work reported here includes a review of the clay types and minerals involved, as well as past mineral processing and extractive metallurgy test work, and reports new research results from renewed investigation of the deposit as a polymetallic resource. This renewed work has found lithium contents that exceed 1,000 ppm, lying directly below the overlying Mercer coal, where the alumina content ranged from 32 to 34 wt%. Total rare earth concentrations were somewhat lower than have been found elsewhere in the region, and the highest contents were also found to be stratigraphically close to the coal. Further work is required to establish the mineral hosts for lithium and rare earths and to define the extent of enriched alumina, lithium, and rare earth concentrations.

Jul 22, 2021

By Anu Martikainen

Utilization of belt air in underground coal mines has been discussed extensively during the last decade. The Final Report of the Technical Study Panel on the Utilization of Belt Air and the Composition and Fire Retardant Properties of Belt Materials in Underground Coal Mining formed by the Miner Act of 2006 recommends research on leakage, use of booster fans, and escapeway safety. This paper discusses the role of ventilation modeling in evaluating primary escapeway pressurization in a three-entry development system to improve emergency escape in a coal mine using belt air. The intake entry of the NIOSH Bruceton Experimental Mine was pressurized using a 1.1 m (42 in) diameter, 37 kW (50 hp) fan. The work details air movement in the simulated three-entry system and the resulting leakage patterns. Three mine ventilation software packages were compared to analyze their performance in predicting the airflows and leakage conditions with different fan settings. NIOSH researchers found that the measurement results correlated well with the results of modeling.

Jan 1, 2010

By R. Hogg

"Some basic features of the science and technology of particle systems are reviewed in the context of agglomeration processes. Emphasis is placed on the force of interaction among particles and with their environment and on their dependence on particle characteristics and interfacial phenomena. The complex role these forces play in the various stages of agglomerate formation, growth, consolidation and structure development, and their influence on final product properties is discussed.INTRODUCTION Agglomeration is an example of a process where the technology has generally preceded the science. Process development• has very often been by trial-and-error albeit with an eye on some basic principles. Nevertheless there is' a scientific basis to the process and a better understanding of the fundamentals can surely lead to improvements in process design and control.Successful processes for the agglomeration of fine particles depend on proper control of the adhesional forces between particles, to encourage agglomerate formation and growth and to provide adequate mechanical strength in the product. At the same time the rheology of the particulate system can be critical to the rearrangement of particles necessary to permit densification of the agglomerate and the development of an agglomerate structure appropriate to the end-use requirements.AGGLOMERATION SYSTEMSUltimately, the performance, of any agglomeration process depends on the• characteristics of the particles and their environment. The specific effects, however, are often complex and may be very difficult to pinpoint by simple observation of the process. A typical agglomeration process involves a number of concurrent or consecutive steps - adhesion, growth, compaction, etc., - each of which is affected by the characteristics of the system, but not necessarily in the same way. The effect of particle size, say on agglomerate growth may be quite different from its effect on compaction and its optimum value may differ widely from one stage to the other. Obviously there.is a general need for compromise in the design and operation, of agglomeration systems. Furtnermore, an understanding of the details of the process and their complexities can be critical to process optimization and improved product quality control."

Jan 1, 1989

By H. K. Lin

The free-milling ore characteristics of the Fort Knox gold deposit are ideal for studying gold and silver behaviors in various processing circuits without serious interference of sulfide minerals and other refractory factors. A galvanic effect leads to faster silver dissolution than gold dissolution and, as a result, the Au/Ag solution concentration ratio increases through the leach circuit. In the CIP circuit, Au adsorption is more effective than Ag adsorption. The Au/Ag solution concentration ratio decreases from 10.0 to 1.0 as the slurry advances from CIP tank #1 to CIP tank #5, while Au/Ag ratio in the carbon increases from 3.2 to 15.3, as the carbon advances from CIP tank #5 to CIP tank #1. Silver is stripped more effectively than gold from the loaded carbon. The Au/Ag ratio in solution reaches 2.0 in the first 75,700 L of strip solution that pass through the loaded carbon; as the stripping process continues, the Au/Ag ratio in the strip solution increases. In the electrowinning circuit, the Au/Ag ratio in the spent electrowinning solution is significantly lower than that in the electrowinning feed, indicating that Au is more rapidly deposited onto the cathode than Ag.

Jan 1, 2010

By S. R. Clark

"INTRODUCTION Of all the natural resources being taxed by the needs of the modern world, perhaps the most important is the continually expanding demand for water resources. As water becomes scarcer, and increasingly important, new technologies are needed to find innovative ways to preserve this precious resource. In Chile, for example, the mining industry is investing billions of dollars to build desalination plants and pipelines; bringing ocean water as far as 200 kilometers inland to meet their demand and maintain operations. It is a full-blown crisis for that nation and a top priority for their government and economy. It has been reported that world water consumption will increase by 40 percent in the next 10 years, representing nearly exponential growth. In the U.S., as more and more communities continue to be built, more drain on the current water infrastructure is created. For 25 percent of people and operations that rely on water from aquifers, this source is being consumed at a rate that will create significant problems meeting the demand in as few as two generations.1 A PROACTIVE APPROACH When it comes to controlling dust at your operation, whether a landfill, a transfer station, a haul road or another ancillary area, what are the options? We know watering is not the answer, but at the same time, we need to prevent dust from flying to ensure a safe environment and keep our skies clear of pollution, for both regulatory requirements and neighbors. Creating a Dust Mitigation Program instead of looking to buy the first dust control product off the shelf is a first step to conserve water and, at the same time, maintain the operational demands and environmental standards for a given site. The program concept is straightforward enough. However, the process of effectively constructing and executing a program is quite involved. When undertaking a program, each manager needs to work with their team and their partners/vendors in analyzing the following elements: 1. Site Expectations—It is important to understand how to balance your internal standards with your regulatory requirements, as well as how to keep your neighbors satisfied. 2. Site Aggregate—Variations in native soil, such as clay content or gravel levels, greatly affect the approach that will yield the highest results. 3. Climate—Relative humidity and seasonal variations are critical to achieving predictable results through product choice, application frequency and timing. 4. Daily Traffic—The type and frequency of traffic is an essential variable for site management. 5. Environmental Responsibilities—If you have additional, specifically defined responsibilities, the approach to your site may vary. 6. Budget—While efficiency is the goal of any program, some sites will have more stringent restrictions than others. 7. Current Usage Rates—Document and understand where you’re starting from, both with water, supporting products, and maintenance so that effective measurement of results is possible."

Jan 1, 2018

By Robert L. Grayson, Syd S. Peng

"An airborne dust study was undertaken at a Southwestern Pennsylvania underground bituminous coal mine by the Pennsylvania Department of Mines and Mineral Industries in 1964 for the purpose of making recommendations and requirements regarding compliance with health and safety aspects of The Bituminous Coal Mining Laws of Pennsylvania, approved by the legislature on July 17, 1961. The study was designed to accurately represent the airborne dust conditions of the subject mine. Sampling by midget impinger of specific worker locations throughout the mine was accomplished. Sample analyses yielded dust concentrations to mppcf, particle size determinations in cumulative per cent less than specified cut-off diameters, and determinations of free silica percentages in total dust samples. The data from this study is further analyzed, and the results are presented.INTRODUCTIONThe Bituminous Coal Mining Laws of Pennsylvania, enacted in 1961, prompted a study of respirable coal mine dust by the Department of Mines and Minerals Industry in 1964. In recognition of their obligation for ensuring the health and safety of bituminous coal miners, the department set out to characterize the airborne dust of mines throughout the commonwealth. The purpose of the studies was to make recommendations and requirements for compliance with the law and for control of airborne coal mine dust in Pennsylvania mines.One such study was undertaken at an underground bituminous coal mine operating in the Pittsburgh Seam in Southwestern Pennsylvania. The study was desig11ed to sample specific worker locations throughout the mine site and characterize the respirable dust relative to each of them. A midget impinger was used to gather respirable range dust samples during an 8-hour shift. Continuous miner operator, roof bolter, stoper bolter, loading machine operator, shuttle car operator, gathering motorman, mainline motorman, and rotary dumper jobs were sampled underground. In addition, barge mover, coal sampler, fine coal operator, heavy media operator, and boiler room attendant occupations were sampled on the surface. The surface sampling was over a 71-hour shift because of UMWA contract provisions."

Jan 1, 1988

By Mary E. Learmont

Grinding with steel media adversely affects the flotation response of galena. Electrochemical measurements, flotation tests, and AES, XPS, and STEM examinations were employed to identify interactions between galena and mild steel. Iron oxide, hydroxide, or sulfate species that formed on the galena surface upon contact with mild steel decreased its floatability, with the time of contact and aeration condition affecting the severity of the flotation depression.. Parallel tests performed with an active metal, magnesium, indicated that floatability was also affected by the presence of a surface coating involving lead species.

Jan 1, 1984

By K. Kim, T. M. Yegulalp

A new explanation of the scale dependency of rock strength is presented based on the theory of extremes. A brief review of past work on specimen size and strength relationship is followed by an introduction to the fundamentals of the underlying theory of extremes and its relationship to the scale effect. It is shown that the weakest link theory is directly related to extremal statistics and that parameters of strength distributions of rock can be derived as a function of the specimen size. Three sets of Brazilian test data are used to demonstrate the use of this approach.

Jan 1, 1994

By L. S. Beck

"The Athabasca region forms part of the Churchill province of the Canadian Shield and is underlain by an Archean or Aphebian assemblage of rocks that underwent severe metamorphism and granitization during the Hudsonian orogeny (1750-1950 m.y. ago). In places, the eroded orogen is overlain by unmetamorphosed cover rocks (in-cluding the Martin and Athabasca formations) of probable Paleohelikian age. Basic dykes cut all the rocks of the region.There are innumerable vein-type pitchblende deposits and many syngenetic occurrences of uraninite in crystalline basement rocks. Evidence is presented to show that pitch-blende was emplaced during the final stages of the Hud-sonian granitization and followed the crystallization of syngenetic uraninite transitionally. In terms of P-T condi-tions, the pitchblende deposits belong essentially to Lindgren's mesothermal group.Based on the postulated uranium metallogenesis, the possibilities of finding further deposits of pitchblende and other types of uranium deposits are discussed."

Jan 1, 1970